Silybum marianum and Notobasis Syriaca belong to the most widespread thorny plants in the Middle East, the Mediterranean, and large areas of Asia. Both plants are derived from the Asteraceae family.

The aim of this study was to compare the phytochemical content of the two plants, the scavenging activity of free radicals, and to evaluate the anti-inflammatory activity of their fruit extracts in vitro.

Methanol extracts of the fruits were prepared from both plants. The activity of scavenging free radicals was studied using DPPH, and the anti-inflammatory activity was investigated in-vitro using soybean lipoxygenase, in comparison with quercetin as standard.

The qualitative phytochemical screening of the fruits showed that both plants contained flavonoids, and coumarins. Both plants showed negative results with alkaloids, saponins, and anthraquinone. The fruit extract from Notobasis Syriaca has the highest capacity to scavenge free radical DPPH (IC50=22.1 mcg/mL), and it has higher ability to inhibit soybean lipoxygenase in-vitro (IC50= 2.7 mcg/mL) than fruit extract from Silybum marianum (IC50= 9.8 mcg/mL).

This study showed that Silybum marianum and Notobasis Syriaca have a high ability to scavenge free radicals; and that both plants possess anti-inflammatory properties